1. Field of the Invention
The present invention relates to efficient gas burners for burning natural gas, manufactured gas and propane gaseous fuels. More particularly, the present invention relates to a high efficiency burner for clean burning gas fuels to provide decorative flames which simulate wood burning.
2. Description of the Prior Art
Gas logs made of fire resistant ceramic materials are well known. Heretofore when such gas logs were employed with a gas burner, the gas flame was usually directed into contact with the gas logs so as to produce an efficient clean blue flame or a highly inefficient and dirty yellow flame. Heretofore the blue flame associated with the clean burning of gas from a gas burner used in conjunction with artificial gas logs was immediately recognized as an artificial log fire flame with little or no aesthetic appeal or natural flame appearance. Alternatively the prior art pipe burners supplied an excessive amount of gas and directed the gas flames onto the gas logs which acted as a heat damper or heat sink, thus, creating excessive soot and carbon monoxide (CO). This latter type of dirty flame was found to produce an orange flame which to some extent simulates or emulates the flame produced by burning wood logs.
The Emission Pollution Control Agency of the United States government (EPA) has promulgated regulations concerning emissions standards for wood-burning stoves and wood-burning fireplaces. These regulations are placing a renewed emphasis on finding new ways to clean burn solid fuels as well as gaseous fuels which are abundantly available in the United States.
Present gas burning logs that are designed to produce decorative flames which simulate burning of wood logs either do not meet the American National Standards Institute (ANSI) emission and safety standard Z-21.50 (1986) or have been limited to producing short blue flames.
Manufacturers of gas log burner systems have heretofore placed a gas burner in a bed of sand or vermiculite to provide a sand pan burner which is placed beneath artificial gas logs. The layer of vermiculite or sand produces an appearance of smoldering or burning embers with a mixture of blue and orange flames which impinge on the ceramic logs and produce excessive amount of carbon monoxide and soot.
Another problem that arises with gas burning logs is that the burner may be adjusted to a very low flame so that the flame burns efficiently with a short blue flame and does not impinge excessively on the ceramic gas log. When such a burner system is employed the amount of heat that is produced by the gas log system is less than the heat which is lost up the chimney. When such systems are installed in a masonry fireplace, the fire underwriters require that the damper be removed from the chimney to provide an open damper system as is required for gas fuel. It has been found that attempts to use efficient short blue flames with gas burners and open damper masonry chimneys create a situation which is prone to flame out due to down draft of air in the chimney, especially in areas where high or swirling winds are present.
It has been suggested that efficient gas burners be incorporated into direct-vented gas fireplaces of the type shown and described in our co-pending application Ser. No. 927,744 filed 11 June 1986. When the prior art gas burner systems are incorporated into side vented or direct vented gas fire places of the type shown and described in application Ser. No. 927,744, they must meet the ANSI emission standards which have been adapted by the American Gas Institute. When the prior art clean burning gas burners are employed, the blue flame is not acceptable to the aesthetic eye. However, when the prior art flame is burned inefficiently to produce a yellow flame to simulate burning of natural wood it does not meet the emission standards set forth by the government and accepted by the American Gas Institute.
There is a present and long felt need for gas log burner systems which will burn clean and which simulate the flame produced by burning wood logs. Therefore, it is desirable to provide a reliable gas log burner system which produces a yellow decorative flame that simulates burning wood logs and which provides efficient usable heat and still meets the EPA regulations and ANSI emissions and safety standards.